You mean like they have been for the past 30 - 40 years. Yeah let's blame Brexit for all that
The historic savings ratio in the UK is around 9% (ie, people save 9% of their disposable income). It fell dramatically in the run-up to the GFC in 2008, then rose again as people reacted to the crisis by reining in their expenditure. A year ago the ratio had fallen back to 6.1%. In Q1 of this year it fell to 1.7%. The issue isn't one of "blaming Brexit"....but rather the fact that, for the past year, UK plc has been supported by a massive debt-fuelled spending spree. It cannot carry on, as we are now significantly more in debt than we were just before the GFC (even after adjusting for inflation).
The private consumer is running out of money. Inward investment in the UK is declining. Businesses are putting investments on hold. We are the poorest performing economy in the EU. And it's going to get worse.
However, as we all know, Brexiteers DID vote to become poorer, so when they lose their jobs, can't get access to basic healthcare, etc, they will still be happy because they have "got back control" (Ooops - forgot - there's going to be a new international court to regulate our on-going relationship with Europe; we will still need to adhere to all the EU regs in order to trade with the EU; and we will have to accept much worse terms to trade with the rest of the world because we have next to zero bargaining power). Some time soon Colonel Blimp will realise that the rest of the world can get along quite nicely without us. Happy Days!